Sorting in groups

Hi,

I am looking at a slightly different sorting problem and I am not sure how to do it in bash.

I have the following input:

I want to sort this, but in groups of three elements with the first one being the sorted value. For example line 16 is lesser than line 13 in the input and it must be re-sorted as the following. The two lines following the sorted value must be moved along with it.

Any pointers to do this is much appreciated.

Thanks!
Jamie